Braille was invented more than 175 years ago to provide a system that blind people can use to read and write. Braille is a system of raised dots that can be read very quickly with the fingers. Braille embossing involves pressing one or more pins of a set of blunted embossing pins arranged in a Braille cell into a printing medium, such as a sheet of heavy paper, to stretch the printing medium and create a corresponding one or more raised dots. Early manual systems for writing in Braille included a slate with holes arranged in rows of Braille cells and means for securing a piece of paper to the slate, and a blunted awl or stylus which was pressed into the paper to create the raised dot or dots, using the holes in the slate as a guide. Later, mechanical impact printers or Braille embossers were created to increase speed and efficiency of embossing, the first such embosser being the Perkins Brailler, originally manufactured in 1951 by the Perkins School for the Blind, based in Watertown, Mass. Currently, Braille writers exist in either mechanical or electronic formats. Examples of the former include the Braille Writer manufactured by the Perkins School for the Blind; the Tatrapoint and Jot-A-Dot writers manufactured by Quantum Technology of Rydalmere, Australia; the Erika Picht mechanical Braille writer manufactured by Blista-Brailletec gGmbH of Marburg, Germany; and the Lavender Braille Writer manufactured by American Printing House for the Blind, Inc. of Louisville, Ky. Examples of electronic Braille writers include the Mountbatten from Quantum Technology of Rydalmere, Australia.
Few ways exist to effectively erase an embossed Braille cell from a printing medium. Originally, a user of a Braille slate and stylus or mechanical Braille writer would press or rub their finger or a blunt instrument against an incorrectly embossed cell to press the raised dots of the cell back to a flattened state. Later, both mechanical and electrical Braille writers would incorporate similar erase mechanisms in which the embossed cell was pressed between two flat plates to press the dots back to a flattened state. However, these methods frequently fail to fully flatten or erase one or more dots of the cell. As a result, a cell printed over the poorly-erased cell may be corrupted.